Power steering system

Abstract

An input shaft and an output shaft can rotate relative to each other. Pressure supplied to a pressure-responsive actuator depends on the axial position of a movable valve member. A transmission arrangement serves to move the valve member only in the axial direction as the input and output shafts rotate relative to each other. The valve member and each of the input and output shafts are wholly outside one another.

What is claimed is: 
     
       1. A power steering system comprising: (a) an input shaft and an output shaft;   (b) a deformable torsion bar connected between the input and output shafts for allowing the input shaft to rotate relative to the output shaft in response to a steering force transmitted to the input shaft;   (c) a pressure-responsive actuator;   (d) a control valve including a movable valve spool and being operative to adjust pressure supplied to the actuator in accordance with the axial position of the valve spool, the valve spool and the input shaft being wholly outside one another, the valve spool and the output shaft being wholly outside one another; and   (e) means for moving the valve spool only in the axial direction as the input shaft rotates relative to the output shaft, said moving means including: (a) a sleeve movably encircling the input and output shafts;   (b) a movable member disposed within a space defined by a groove in the input shaft, a groove in the output shaft oblique to the groove in the input shaft, and a recess in the sleeve; and   (c) means for connecting the sleeve and the valve spool.     
     
     
       2. The power steering system of claim 1, wherein the groove in the input shaft extends axially and the groove in the output shaft extends spirally. 
     
     
       3. The power steering system of claim 1, wherein the groove in the input shaft extends spirally and the groove in the output shaft extends axially. 
     
     
       4. The power steering system of claim 1, wherein the movable member comprises a ball. 
     
     
       5. A power steering system comprising: (a) an input shaft and an output shaft;   (b) a deformable torsion bar connected between the input and output shafts for allowing the input shaft to rotate relative to the output shaft in response to a steering force transmitted to the input shaft;   (c) a pressure-responsive actuator;   (d) a control valve including a movable valve spool and being operative to adjust pressure supplied to the actuator in accordance with the axial position of the valve spool, the valve spool and the input shaft being wholly outside one another, the valve spool and the output shaft being wholly outside one another; and   (e) means for moving the valve spool only in the axial direction as the input shaft rotates relative to the output shaft, said moving means including: (a) a sleeve encircling the input shaft;   (b) means connecting the sleeve to the output shaft for corotation while allowing the sleeve to move axially;   (c) a movable member disposed within a space defined by an oblique groove in the input shaft and a recess in the sleeve;   (d) a connecting member fixed to the valve spool; and   (e) a bearing disposed between the sleeve and the connecting member for allowing the sleeve to rotate relative to the connecting member.     
     
     
       6. A power steering system comprising: (a) an input shaft and an output shaft;   (b) a deformable torsion bar connected between the input and output shafts for allowing the input shaft to rotate relative to the output shaft in response to a steering force transmitted to the input shaft;   (c) a pressure-responsive actuator;   (d) a control valve including a movable valve spool and being operative to adjust pressure supplied to the actuator in accordance with the axial position of the valve spool, the valve spool and the input shaft being wholly outside one another, the valve spool and the output shaft being wholly outside one another; and   (e) means for moving the valve spool only in the axial direction as the input shaft rotates relative to the output shaft, said moving means including: (a) a sleeve encircling the input shaft;   (b) means connecting the sleeve to the output shaft for corotation while allowing the sleeve to move axially;   (c) a movable member disposed within a space defined by an oblique groove in the input shaft and a recess in the sleeve;   (d) a connecting member fixed to the valve spool; and   (e) a bearing disposed between the sleeve and the connecting member for allowing the sleeve to rotate relative to the connecting member, said bearing being supported by a housing and movable in the axial direction with the sleeve.